The present invention relates to a refrigerant composition for use in refrigeration systems, and which has potential for ozone-depletion in the ozonosphere, as well as a binary refrigeration system using the composition.
Conventionally, R12 (dichlorodifluoromethane) and R500 (an azeotropic mixture of R12 and R152a (1,1-difluoroethane)) have often been used as refrigerants for refrigeration systems. The boiling points of R12 and R500 are about -30.degree. C. and -33.degree. C., respectively, which are suitable to usual refrigeration systems. Further, even if their compressor inlet temperatures are comparatively high, their compressor outlet temperatures do not rise so high as to cause oil-sludge in the compressor. Further, R12 is highly compatible with an compressor oil and, hence, plays a role of returning the oil in the refrigerant circuit to the compressor.
On the other hand, for achieving a lower temperature region of lower than -80.degree. C., R503 (an azeotropic mixture of R23 and R13 ) is used. The boiling point of R503 is -88.65.degree. C., which is suitable for obtaining a low temperature.
However, it is considered that each of the abovementioned refrigerants has a risk of destroying the ozonosphere and the use thereof has now been restricted. That is, R12 constituting R500 or R13 constituting R503 is a less decomposable so-called regulated refrigerant and it has been found that when it is released in the atmosphere and reaches an ozonosphere, there is a risk of destroying the ozonosphere.
At present, refrigerants capable of substituting the above-mentioned regulated refrigerants have now been under study and search by researchers in the world.